A mooring is a fixture to which a device may be secured. At sea there are many mooring methods that can be used to secure a device to the seabed. The main categories of moorings are identified below, however there are other options available – see Aquaret website for more details.
Gravity based structures rely on the mass of the structure to keep it in place. In some cases there may be additional fixing to the seabed.
This principle is analogous to that used to mount most large wind turbines, whereby the device is attached to a pole penetrating the ocean floor. Horizontal axis devices will often be able to yaw about this structure. This may also allow the turbine to be raised above the water level for maintenance.
Hydrofoil inducing downforce
This device uses a number of hydrofoils mounted on a frame to induce a downforce from the tidal current flow. Provided that the ratio of surface areas is such that the downforce generated exceeds the overturning moment, then the device will remain in position.
Flexible mooring: The device is tethered via a cable/chain to the seabed allowing considerable freedom of movement. This allows a device to swing as the tidal current direction changes with the tide. A flexible system is also required for many wave energy converters to allow the required movement.
Rigid mooring: The device is secured into position using a fixed mooring system, allowing minimal leeway.
Examples of moorings and anchors
All the mooring and anchor examples provided in the below gallery have been used across the tidal, wave and floating wind industry. It’s important to note that given the complex nature of marine engineering and environmental conditions that the moorings can be used across a variety of technologies.
To download the above animations please visit the Aqua-RET website